My 1992 PS190 is back firing at around 3200 RPM and then it starts to die. I think it might be one or more of the following: cap, rotor, wires, plugs or the coil.

What is the best way to determine which part might be the issue? The plugs are easy to tell if they are bad but I'm not sure how to diagnose the other parts.

Any help would be great.

Thanks

BrianM

09-06-2011, 07:36 PM

How long has it been since this stuff was changed? More than likely not going to be the coil as they are usually either dead or alive. The other parts are relatively cheap if its been a couple of years since you have changed them I would do them all.

That being said are you sure it isn't a fuel problem? When was the last time the carb was rebuilt?

oldairboater

09-06-2011, 09:13 PM

Replace cap, rotor, wires and plugs. If that doesn't fix it. Then look at fuel delivery. Usually my problems are ignition first fuel second.

prostar190jap

09-08-2011, 11:19 AM

How long has it been since this stuff was changed? More than likely not going to be the coil as they are usually either dead or alive. The other parts are relatively cheap if its been a couple of years since you have changed them I would do them all.

That being said are you sure it isn't a fuel problem? When was the last time the carb was rebuilt?

I just had the carb rebuilt last month. It was completely torn down and rebuilt. I learned my lesson the last time it was rebuilt by the MC dealer. They didn't even take it off the engine. I took to a guy that only rebuilds boat carbs.

rjracin240

09-08-2011, 11:49 AM

I just had the carb rebuilt last month. It was completely torn down and rebuilt. I learned my lesson the last time it was rebuilt by the MC dealer. They didn't even take it off the engine. I took to a guy that only rebuilds boat carbs.

If it is backfiring through the carb (running lean) then take another look at the Carburettor.

Otherwise probably pretty safe to assume it is electrical.

thatsmrmastercraft

09-08-2011, 12:21 PM

Another possible source for backfiring through the carb is a flat(worn out) camshaft.

prostar190jap

09-08-2011, 12:36 PM

If it is backfiring through the carb (running lean) then take another look at the Carburettor.

Otherwise probably pretty safe to assume it is electrical.

I think it might be electrical. The plugs cap and rotor were replaced almost two years ago. I found a lot of fine dust under the cap.

JMann

09-08-2011, 03:10 PM

If you just had the carb rebuilt I would guess it's something on the carb. Did they take the boat out after the rebuilt to adjust the carb and it was running fine? If not I would ask them to adjust the carb. If they didn't and it was running fine i would guess electrical. I just rebuilt my carb and someone gave me this link in my thread about adjusting your carb.
Which carb do you have the 4150 or 4160?

http://holley.com/data/Products/Technical/199R9808.pdf

prostar190jap

09-08-2011, 03:24 PM

If you just had the carb rebuilt I would guess it's something on the carb. Did they take the boat out after the rebuilt to adjust the carb and it was running fine? If not I would ask them to adjust the carb. If they didn't and it was running fine i would guess electrical. I just rebuilt my carb and someone gave me this link in my thread about adjusting your carb.
Which carb do you have the 4150 or 4160?

http://holley.com/data/Products/Technical/199R9808.pdf

I just gave him the carb. He tests everything on a flow bench and makes adjustments. When I re-installed the carb, the boat fired up no problem.

I just talked to my cousin (he had it out last) and he said it was doing the same thing before the carb was rebuilt. I have the 4150.

thatsmrmastercraft

09-08-2011, 03:27 PM

Another source for backfiring through the carb is wrong firing order. I would verify that next.

theoldgirl1990

09-08-2011, 05:11 PM

I actually had the same problem with my 1991 after we did a high performance rebuild on it. It ended up being that it was jetted to rich cause there was raw fuel out the back. Even if your carb is rebuilt it might not be jetted correctly. Most carbs come jetted for sea level. Just a thought.